ing sixteen. Among major religious groups, only black Protestants begin hav- ing sex earlier. Another key difference in behavior, Regnerus reports, is that evangelical Prot- estant teen-agers are significantly less likely than other groups to use contracep- tion. This could be because evangelicals are also among the most likely to believe , \., " you look at the outcomes of abstinence- pledge movements. Nationwide, accord- ing to a 2001 estimate, some two and a half million people have taken a pledge to remain celibate until marriage. Usu- ally, they do so under the auspices of movements such as True Love Waits or the Silver Ring Thing. Sometimes, they make their vows at big rallies featuring ,. "" ..... '- . '" ...... , , rates of S.T.D.s. This could be because more teens pledge in communities where they perceive more danger from sex (in which case the pledge is doing some good); or it could be because fewer peo- ple in these communities use condoms when they break the pledge. Bearman and Brückner have also identified a peculiar dilemma: in some The "sexual début" of an evangelical girl typically occurs just after she turns sixteen. Photograph by Mary Ellen Mark. that using contraception will send the message that they are looking for sex. It could also be because many evangelicals are steeped in the abstinence movement's warnings that condoms won't actually protect them from pregnancy or venereal disease. More provocatively, Regnerus found that only half of sexually active teen-agers who say that they seek guid- ance from God or the Scriptures when making a tough decision report using contraception every time. By contrast, sixty-nine per cent of sexually active youth who say that they most often fol- low the counsel of a parent or another trusted adult consistently use protection. The gulfbetween sexual belief and sex- ual behavior becomes apparent, too, when Christian pop stars and laser light shows, or at purity balls, where girls in frothy dresses exchange rings with their fathers, who vow to help them remain virgins until the day they marry. More than half of those who take such pledges-which, unlike abstinence-only classes in public schools, are explicitly Christian-end up having sex before marriage, and not usu- ally with their future spouse. The move- ment is not the complete washout its critics portray it as: pledgers delay sex eigh- teen months longer than non-pledgers, and have fewer partners. Yet, according to the sociologists Peter Bearman, of Columbia University, and Hannah Brückner, of Yale, communities with high rates of pledging also have high schools, if too many teens pledge, the effort basically collapses. Pledgers appar- ently gather strength from the sense that they are an embattled minority; once their numbers exceed thirty per cent, and pro- claimed chastity becomes the norm, that special identity is lost. With such a fragile formula, it's hard to imagine how educa- tors can ever get it right: once the self- proclaimed virgin clique hits the thirty- one-per-cent mark, suddenly it's Sodom and Gomorrah. R eligious belief apparently does make a potent difference in be- havior for one group of evangelical teen- agers: those who score highest on mea- sures of religiosity-such as how often THE NEW YORKER, NOVEMBER 3, 2008 65